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On some peculiarities of electric field pulse propagation in electron Maxwellian plasma and its back response

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 Added by Viktor Soshnikov
 Publication date 2006
  fields Physics
and research's language is English




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In the spirit of continued study of general plasma wave properties we investigated the boundary problem with the simplest form of electric field pulse at the edge x=0 of half-infinite uniform plasma slab with Maxwellian electron distribution function. In the case of longitudinal electric field pulse its traveling velocity is essentially other than in the case of harmonic waves; there is also no back response. In the case of transverse field pulse there takes place the bimodal propagation rate of the non-damping fast pulse signal and non-damping weak slow sign reversed pulse signals; some very weak response (echo) arises with a time delay in the near coordinate zone of formation of the asymptotical regime.



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113 - V. N. Soshnikov 2007
It is shown in linear approximation that in the case of one-dimensional problem of transverse electron waves in a half-infinite slab of homogeneous Maxwellian collisionless plasma with the given boundary field frequency two wave branches of solution of the dispersion equation are simultaneously realizing. These are the branch of fast forward waves determined mainly by Maxwell equations of electromagnetic field, as well as the branch of forward and backward slow waves determined in the whole by kinetic properties of electrons in the collective electrical field. The physical nature of wave movements is revealed. A relation is found between electric field amplitudes of fast and slow waves. Multiform dividing the coupled slow waves into standing and traveling parts leads to a necessity of additional requirements to a selection of the type of a device analyzing these waves and its response interpretation.
200 - V. N. Soshnikov 2008
In this paper we have criticized the so-called Landau damping theory. We have analyzed solutions of the standard dispersion equations for longitudinal (electric) and transversal (electromagnetic and electron) waves in half-infinite slab of the uniform collisionless plasmas with non-Maxwellian and Maxwellian-like electron energy distribution functions. One considered the most typical cases of both the delta-function type distribution function (the plasma stream with monochromatic electrons) and distribution functions, different from Maxwellian ones as with a surplus as well as with a shortage in the Maxwellian distribution function tail. It is shown that there are present for the considered cases both collisionless damping and also non-damping electron waves even in the case of non-Maxwellian distribution function.
We consider the possibility of formation of a superconductivity state either in a semiconductor or in a electron-hole plasma with the degenerate electrons due to the attractive forces between the electrons as a result of the exchange effects through the electron-hole sound wave by analogy to the phonon waves in a solid state. We have determined the view of an interaction potential between two electrons in a degenerate electron-hole plasma. The potential appears to be attractive at distances large than the Debye radius and decreases as $1/r^3$. We discuss the conditions at which the bound electron state - Cooper Pair in a such field can be formed.
289 - V. N. Soshnikov 2014
We have considered an expansion of solutions of the non-linear equations for both longitudinal and transverse waves in collisionless Maxwellian plasma in series of non-damping overtones of the field E(x,t) and electron velocity distribution function f=f(0) +f(1) where f(0) is background Maxwellian electron distribution function and f(1) is perturbation. The electrical field and perturbation f(1) are presented as a series of non-damping harmonics with increasing frequencies of the order n and the same propagation speed. It is shown presence of recurrent relations for arising overtones. Convergence of the series is provided by a power law parameter series convergence. There are proposed also successive procedures of cutting off the distribution function f(1) to the condition of positivity f near the singularity points where kinetic equation becomes inapplicable. In this case, at poles absence the solution reduces to non-damping Vlasov waves (oscillations). In the case of transverse waves, dispersion equation has two roots, corresponding to the branches of fast electromagnetic and slow electron waves. There is noted a possibility of experimental testing appearing exotic results with detecting frequencies and amplitudes of n-order overtones.
In previous experiments by the authors on a magnetic dipole interacting with a laser-produced plasma the generation of an intense field-aligned current (FAC) system on terrella poles was observed. In this paper the question of the origin of these currents in a low-latitude boundary layer of magnetosphere is investigated. Experimental evidence of such a link was obtained by measurements of the magnetic field generated by tangential drag and sheared stress. This specific azimuthal field was found to have quadruple symmetry and local maxima inside the magnetosphere adjacent to the boundary layer. Cases of metallic and dielectric dipole covers modeling good conductive and non-conductive ionosphere revealed that the presence or absence of FACs results in different amplitudes and spatial structures of the sheared field. The current associated with the azimuthal field flows upward at the dawnside, and toward the equator plane at the duskside. It was found to coincide by direction and to correspond by amplitude to a total cross-polar current measured independently. The results suggest that compressional and Alfven waves are responsible for FAC generation. The study is most relevant to FACgeneration in the magnetospheres of Earth and Mercury following pressure jumps in solar wind.
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